1. Field of the Invention
The present disclosure relates to an imaging device that acquires an image (distance image) of an object present in a position away from a predetermined distance, and in particular, relates to an imaging device that acquires a distance image and a normal image (visible light image), and a driving method thereof.
2. Description of the Related Art
In the related art, for example, a ranging camera (motion camera) that emits infrared light to an imaging target space and detects the movement of the body or the hand of an object (person) is mounted in a television, a game machine, or the like, and an imaging device that acquires a distance image used in the ranging camera, in other words, a so-called distance measuring sensor has been known.
It is useful for the distance measuring sensor to acquire the distance image and a normal visible light image at the same time, in terms of cut-out of a specific object from an image (background separation) or preparation of a three-dimensional image.
In PTL 1, a distance image and a visible light image are acquired at the same time by a single solid state imaging device. Specifically, the solid state imaging device, which is made of a single plate and is capable of performing imaging using visible light and infrared (IR) light, emits IR pulses to an imaging target space at each one frame scanning period, while performing the imaging using the visible light and the infrared light at each one frame scanning period. The solid state imaging device generates a visible light image at each one frame scanning period, and generates a distance image excluding the influence of background light in each one frame scanning period, by subtracting an IR pixel signal obtained by performing imaging during non-irradiation of the IR pulses, from an IR pixel signal obtained by performing imaging during irradiation of the IR pulses.